Discord user Night has done some further work with Stable Diffusion/Photoshop. It's almost perect now.
Also, Balsamique had this to say about a common question recently:
"Have you ever thought about porting BtD to another engine like unity or renpy for easier modding?"
"Yes I thought putting BTD on another plateform. I studied the idea and saw it was too difficult. I'd rather do a sequel. I thought about sci-fi investigation game where you play a Bene Gesserit investigator, or a ghola of Duncan Idaho, I also thought about a mix with Vega Hunters... I spend my time thinking about stuff with the new engine of
Horror in Hongdae that is on Unity, everything is possible. "